diff options
Diffstat (limited to 'arch/powerpc/kernel/idle_book3s.S')
| -rw-r--r-- | arch/powerpc/kernel/idle_book3s.S | 130 |
1 files changed, 114 insertions, 16 deletions
diff --git a/arch/powerpc/kernel/idle_book3s.S b/arch/powerpc/kernel/idle_book3s.S index e6252c5a57a4..1125c9be9e06 100644 --- a/arch/powerpc/kernel/idle_book3s.S +++ b/arch/powerpc/kernel/idle_book3s.S @@ -85,7 +85,61 @@ ALT_FTR_SECTION_END_IFSET(CPU_FTR_ARCH_300) std r3,_WORT(r1) mfspr r3,SPRN_WORC std r3,_WORC(r1) +/* + * On POWER9, there are idle states such as stop4, invoked via cpuidle, + * that lose hypervisor resources. In such cases, we need to save + * additional SPRs before entering those idle states so that they can + * be restored to their older values on wakeup from the idle state. + * + * On POWER8, the only such deep idle state is winkle which is used + * only in the context of CPU-Hotplug, where these additional SPRs are + * reinitiazed to a sane value. Hence there is no need to save/restore + * these SPRs. + */ +BEGIN_FTR_SECTION + blr +END_FTR_SECTION_IFCLR(CPU_FTR_ARCH_300) + +power9_save_additional_sprs: + mfspr r3, SPRN_PID + mfspr r4, SPRN_LDBAR + std r3, STOP_PID(r13) + std r4, STOP_LDBAR(r13) + mfspr r3, SPRN_FSCR + mfspr r4, SPRN_HFSCR + std r3, STOP_FSCR(r13) + std r4, STOP_HFSCR(r13) + + mfspr r3, SPRN_MMCRA + mfspr r4, SPRN_MMCR1 + std r3, STOP_MMCRA(r13) + std r4, STOP_MMCR1(r13) + + mfspr r3, SPRN_MMCR2 + std r3, STOP_MMCR2(r13) + blr + +power9_restore_additional_sprs: + ld r3,_LPCR(r1) + ld r4, STOP_PID(r13) + mtspr SPRN_LPCR,r3 + mtspr SPRN_PID, r4 + + ld r3, STOP_LDBAR(r13) + ld r4, STOP_FSCR(r13) + mtspr SPRN_LDBAR, r3 + mtspr SPRN_FSCR, r4 + + ld r3, STOP_HFSCR(r13) + ld r4, STOP_MMCRA(r13) + mtspr SPRN_HFSCR, r3 + mtspr SPRN_MMCRA, r4 + /* We have already restored PACA_MMCR0 */ + ld r3, STOP_MMCR1(r13) + ld r4, STOP_MMCR2(r13) + mtspr SPRN_MMCR1, r3 + mtspr SPRN_MMCR2, r4 blr /* @@ -141,7 +195,16 @@ pnv_powersave_common: std r5,_CCR(r1) std r1,PACAR1(r13) +BEGIN_FTR_SECTION + /* + * POWER9 does not require real mode to stop, and presently does not + * set hwthread_state for KVM (threads don't share MMU context), so + * we can remain in virtual mode for this. + */ + bctr +END_FTR_SECTION_IFSET(CPU_FTR_ARCH_300) /* + * POWER8 * Go to real mode to do the nap, as required by the architecture. * Also, we need to be in real mode before setting hwthread_state, * because as soon as we do that, another thread can switch @@ -151,6 +214,20 @@ pnv_powersave_common: mtmsrd r7,0 bctr +/* + * This is the sequence required to execute idle instructions, as + * specified in ISA v2.07 (and earlier). MSR[IR] and MSR[DR] must be 0. + */ +#define IDLE_STATE_ENTER_SEQ_NORET(IDLE_INST) \ + /* Magic NAP/SLEEP/WINKLE mode enter sequence */ \ + std r0,0(r1); \ + ptesync; \ + ld r0,0(r1); \ +236: cmpd cr0,r0,r0; \ + bne 236b; \ + IDLE_INST; + + .globl pnv_enter_arch207_idle_mode pnv_enter_arch207_idle_mode: #ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE @@ -242,20 +319,27 @@ enter_winkle: /* * r3 - PSSCR value corresponding to the requested stop state. */ -power_enter_stop: #ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE - /* Tell KVM we're entering idle */ +power_enter_stop_kvm_rm: + /* + * This is currently unused because POWER9 KVM does not have to + * gather secondary threads into sibling mode, but the code is + * here in case that function is required. + * + * Tell KVM we're entering idle. + */ li r4,KVM_HWTHREAD_IN_IDLE /* DO THIS IN REAL MODE! See comment above. */ stb r4,HSTATE_HWTHREAD_STATE(r13) #endif +power_enter_stop: /* * Check if we are executing the lite variant with ESL=EC=0 */ andis. r4,r3,PSSCR_EC_ESL_MASK_SHIFTED clrldi r3,r3,60 /* r3 = Bits[60:63] = Requested Level (RL) */ bne .Lhandle_esl_ec_set - IDLE_STATE_ENTER_SEQ(PPC_STOP) + PPC_STOP li r3,0 /* Since we didn't lose state, return 0 */ /* @@ -288,7 +372,8 @@ power_enter_stop: ld r4,ADDROFF(pnv_first_deep_stop_state)(r5) cmpd r3,r4 bge .Lhandle_deep_stop - IDLE_STATE_ENTER_SEQ_NORET(PPC_STOP) + PPC_STOP /* Does not return (system reset interrupt) */ + .Lhandle_deep_stop: /* * Entering deep idle state. @@ -310,7 +395,7 @@ lwarx_loop_stop: bl save_sprs_to_stack - IDLE_STATE_ENTER_SEQ_NORET(PPC_STOP) + PPC_STOP /* Does not return (system reset interrupt) */ /* * Entered with MSR[EE]=0 and no soft-masked interrupts pending. @@ -411,6 +496,18 @@ pnv_powersave_wakeup_mce: b pnv_powersave_wakeup +#ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE +kvm_start_guest_check: + li r0,KVM_HWTHREAD_IN_KERNEL + stb r0,HSTATE_HWTHREAD_STATE(r13) + /* Order setting hwthread_state vs. testing hwthread_req */ + sync + lbz r0,HSTATE_HWTHREAD_REQ(r13) + cmpwi r0,0 + beqlr + b kvm_start_guest +#endif + /* * Called from reset vector for powersave wakeups. * cr3 - set to gt if waking up with partial/complete hypervisor state loss @@ -435,15 +532,9 @@ ALT_FTR_SECTION_END_IFSET(CPU_FTR_ARCH_300) mr r3,r12 #ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE - li r0,KVM_HWTHREAD_IN_KERNEL - stb r0,HSTATE_HWTHREAD_STATE(r13) - /* Order setting hwthread_state vs. testing hwthread_req */ - sync - lbz r0,HSTATE_HWTHREAD_REQ(r13) - cmpwi r0,0 - beq 1f - b kvm_start_guest -1: +BEGIN_FTR_SECTION + bl kvm_start_guest_check +END_FTR_SECTION_IFCLR(CPU_FTR_ARCH_300) #endif /* Return SRR1 from power7_nap() */ @@ -809,9 +900,16 @@ no_segments: mtctr r12 bctrl +/* + * On POWER9, we can come here on wakeup from a cpuidle stop state. + * Hence restore the additional SPRs to the saved value. + * + * On POWER8, we come here only on winkle. Since winkle is used + * only in the case of CPU-Hotplug, we don't need to restore + * the additional SPRs. + */ BEGIN_FTR_SECTION - ld r4,_LPCR(r1) - mtspr SPRN_LPCR,r4 + bl power9_restore_additional_sprs END_FTR_SECTION_IFSET(CPU_FTR_ARCH_300) hypervisor_state_restored: |